Alcohol, Alcohol Denat, and SD Alcohol on a Filing

Someone forwarded me a formula last week where the ingredient list just said "Alcohol" for the ethanol in a facial toner, and the supplier invoice, three tabs over, clearly said "denatured ethanol, IPA-denatured." Those are not the same INCI declaration, and this mismatch is common enough that it deserves its own explanation rather than a footnote in a general solvents post.

Three declarations, one base chemical

All three of these ultimately trace back to ethanol. What differs is whether, and how, that ethanol has been denatured, meaning deliberately adulterated with another substance to make it unfit to drink, usually for tax and regulatory reasons around alcohol production.

Alcohol as an INCI name refers to ethanol in its non-denatured form. This shows up less often in mainstream cosmetics than people assume, because most commercially available cosmetic-grade ethanol is denatured before it ever reaches a formulator, partly for tax reasons in the country of manufacture.

Alcohol Denat. is the INCI declaration for ethanol that has been denatured. This is what you will find in the overwhelming majority of toners, perfumes, hairsprays, and hand sanitizers. The specific denaturant used (which can be things like isopropyl alcohol, tert-butyl alcohol, or denatonium benzoate depending on jurisdiction and formula) does not usually change the INCI name itself, but it can change the CAS reference your supplier cites.

SD Alcohol, followed by a number such as SD Alcohol 39-C or SD Alcohol 40, is a US-specific naming convention tied to specially denatured alcohol formulas recognized by US tax and alcohol regulatory authorities. It is functionally the same category as Alcohol Denat., denatured ethanol, but the number tells you which specific denaturant formula was used under the US system.

Why the distinction actually matters on a filing

Your Cosmetic Notification Form or ingredient declaration should reflect what is actually in the bottle, not a generic placeholder. If your supplier's certificate of analysis says the ethanol is denatured, declaring plain "Alcohol" is inaccurate, even if functionally the ingredient behaves almost identically in your formula. Filings get reviewed against supplier documentation more often than makers expect, and a mismatch between your declared INCI and your supplier's paperwork is exactly the kind of discrepancy that draws a follow-up question.

There is also a practical sourcing angle. If you reformulate or switch ethanol suppliers and the new one uses non-denatured alcohol where the old one used SD Alcohol 40, your ingredient declaration needs to change even if nothing else about the formula moved. Treating "alcohol" as an interchangeable generic term across suppliers is how that kind of quiet formula drift slips past a filing that should have been amended.

How to check which one you have

• Pull the certificate of analysis, not the product name. Trade names for ethanol supply almost never spell out denaturation status clearly in the name itself.
• Look for the denaturant explicitly named. If the paperwork lists a denaturant, you are dealing with Alcohol Denat. or an SD Alcohol variant, not plain Alcohol.
• Confirm the market convention. SD Alcohol numbering is a US labeling habit; outside the US it is more common to just see Alcohol Denat. regardless of which specific denaturant was used.
• Recheck after any supplier switch. Do not assume your new ethanol source uses the same denaturation approach as your old one.

A small table to keep straight

INCI declaration	What it means	Where you'll typically see it
Alcohol	Non-denatured ethanol	Less common; specific formulas requiring pure ethanol
Alcohol Denat.	Denatured ethanol, denaturant unspecified in the name	Toners, perfumes, hairsprays, sanitizers, most markets
SD Alcohol [number]	Denatured ethanol, specific US denaturant formula	US-labeled products following US alcohol tax conventions

Getting this right is a small thing that signals a larger habit: reading supplier documentation instead of trade names when you build your ingredient deck. Cosmetic Comply's ingredient matching is built around exactly that habit, tracing each raw material back to the INCI name its actual composition supports rather than the one its label implies, before that ingredient ever reaches your filing.